C. S. Anoop, Boby George
Study of a Hall Effect Brake Wear Sensor using Finite Element Modelling and Analysis

Monitoring of brake wear and warning the driver to replace it at the appropriate time is a critical safety requirement. Recently, basic concept of a new, simple and low-cost Hall-Effect (HE) based angle sensor, which continuously monitors brake wear, by sensing the angle rotated by the Cam Shaft (CS) with-respect-to the Slack Adjuster (SA) in the brake assembly has been presented. The sensor has a spiral shaped moving part. It rotates along with CS, and changes the magnetic field seen by a HE sensor, whose output is directly proportional to angle between CS and SA, for a wide range. A prototype angle sensor has been developed, and test results showed a linear range of 220°, which is sufficient for monitoring brake wear. In the sensor, parameters like positioning of the HE sensor, relative permeability of the materials used, thickness of the moving part, etc. play a crucial role as far as the linearity of output and sensitivity are concerned. Sensor optimisation based on hardware implementation is time consuming, inefficient and less accurate. Hence, a finite element model of the sensor has been developed, and various studies have been conducted to optimise the parameters for best performance of the sensor. This also enables to achieve a linear output without using complex circuitry.

Wendell. E. M. Costa, Sabiniano A. Rodrigues, Raimundo C. S. Freire, Sebastian Y. Catunda, Thaís L. V. N. Silva, Malone Soares de de Castro, Fernando Rangel de Sousa
A Folding ADC Based on Switched Capacitor Circuits in 350 nm CMOS

This paper presents a 10-bit folding analog-digital converter (ADC) using switched capacitors (SC) circuits. In this architecture, the conversion is achieved when the signal crosses a certain voltage level and at this time, a voltage value is added or subtracted from the analog input signal. The proposed ADC consists in eight identical stages, to perform the conversion of one bit at a time. Each stage is built with a amplifier circuit using switched capacitor with gain 2. The ADC is designed in a standard 350 nm CMOS (Complementary Metal- Oxide-Semiconductor) technology. A conversion time of 570 ns and a SNDR of 56.8 dB were obtained by simulations with the ADC prototype, to a 10 bits resolution converter with 3.3 V power supply and a 8 mW power consumption.

C. Asensio, M. Ruíz, M. Recuero, G. Moschioni, M. Tarabini
Application of intelligent instruments for the monitoring of thrust reverse noise at airports

Many airports all over the world have established some kind of restrictions for the use of thrust reverse for slowing down aircraft after landings, especially during the night period, as a way of reducing noise impact and the number of complaints in the vicinity of airports. This is the case of Madrid airport, where the Universidad Politécnica de Madrid, in collaboration with AENA, and the Politecnico di Milano have been researching, and developing intelligent instruments to improve the detection and classification of thrust reverse noise among other noise sources present in the airport.
Based on a traditional approach, the thrust reverse noise detection tool (TREND) detects two consecutive sound events, and applies pattern recognition techniques for the classification of each of them (such as landing and thrust reverse). A second improvement refers to the use of a microphone array linked to a noise monitoring unit, which enables tracking the direction of arrival of the sound, thus improving the classification rates. By taking the latter, it is also possible to track the aircraft location along the runway, which enables sound pressure measurements to be transformed into sound power level estimations. Although TREND must be optimized and customized, the results have shown quite good classification rates (over 90%).

Jesús Martínez-Teruel, Tomás García-Sánchez, Andreu Fontova, Ramon Bragós
Electrical Impedance Spectroscopy cell monitoring in a miniaturized bioreactor

Electrical impedance spectroscopy measurement of biologic materials provides information about viable cell density as well as cell size and shape homogeneity. Several experimental and even commercial biomass density probes have been developed both for cell suspensions and monolayer cell cultures in the last twenty years. This communication describes the development of a set of electrodes and circuits designed to add viable biomass density measurement capability to a set of single-use miniaturized bioreactors. Two applications: adherent animal cultures and generic cell suspension cultures drive to the need of providing two electrode sets and two measurement systems with different frequency ranges.

Angel Moure, Pedro Torres
Low Power and High Effiency Energy Acquisition Systems for Volcano Monitoring

Two acquisition systems have been developed to acquire low sampling rate parameters (volcanic gases content and meteorological parameters) related with volcano activity. The first device (gDT316) is a 16 bits five-channel datalogger with a SD storage. The second one (gCNT16) is a simple three-channel 16 bits counter with EEPROM storage. Their main characteristics are low power consumption and low cost manufacturing. Here we describe both devices and the first three examples retrieved applying them on a volcano monitoring network (Tenerife Island, Spain).